In drive mechanisms it is often desirable to minimize dimensions of the mechanisms in order to make maximum use of space limited mounting locations. For example, a drive mechanism is commonly mounted within a drum or roller of a compactor to rotate the drum. In a vibratory compactor, a vibrating mechanism is also positioned within the drum to impart vibratory forces to the drum. Such a vibratory compactor is illustrated in U.S. Pat. No. 4,108,009 which issued to Fuchigami on Aug. 22, 1978. If both the drive and vibrating mechanisms are utilized, the amount of space within the drum can become very limited. It is not uncommon, therefore, to mount a hydraulic motor, which provides the rotational input to the drive mechanism, outside of the drum. Such a mounting arrangement is shown in U.S. Pat. No. 3,741,669 which issued on June 26, 1973 to Harris. In certain work environments, such a mounting arrangement can subject the exteriorly mounted components to damage from, for example, contacting obstructions in turning the associated vehicle.
Also contributing to the space limitations inside a drum is the problem of obtaining the most desirable final rotational speed of the drum relative to the input of the motor. This sometimes can require numerous sets of gears in the drive mechanism to change the speed of the rotational input. Use of a plurality of gear sets to change speeds particularly affects the width of a drive mechanism which can further limit the space available inside the drum for mounting the vibratory drive mechanism.
The present invention is directed to overcoming one or more of the problems as set forth above.